Field of the Invention
The invention relates to a stepping motor which prevents movements of a moving member.
Discussion of Related Art
Stepping motors are used to precisely control a mechanical movement amount, which may be digitally controlled by a pulse. Due to this, stepping motors are used for adjusting a direction and an angle of an automotive lamp or for a light pickup of an optical disc driver, which needs precise control.
In stepping motors, a lead screw inserted in a bracket rotates, thereby linearly moving a transfer nut to control a movement amount. However, since the transfer nut is coupled only with the lead screw, the transfer nut easily moves due to external shocks in such a way that it is difficult to perform precise control.
To overcome this, a supporting rod is inserted into the transfer nut to restrain vibrations. However, it is difficult to restrain vibrations only using the supporting rod.
Also, since it is necessary to precisely adjust concentricity between a through-hole for inserting the lead screw and a through-hole for inserting the supporting rod, productivity decreases. Also, when the concentricity is not precise, stepping motors are not driven.
Also, since it is necessary to manually insert the lead screw into the bracket, an operation pace becomes decreased.